More than 80 million children and mothers will needlessly die in the developing world by 2015 unless urgent action is taken, say UK aid agencies.
Millions of children are at risk from treatable diseases
The international community has pledged to significantly cut child and mother mortality rates over the next 12 years.
But in a report, ahead of the annual meeting of the World Bank and IMF, aid agencies said the situation in many countries is getting worse rather than better.
They said ensuring people have access to basic healthcare, clean water and sanitation would prevent these deaths.
The Millennium Development Goals - agreed by UN member states three years ago - aim to cut child mortality by two thirds and maternal death rates by three quarters by 2015.
However, this latest report suggests many countries will struggle to meet these targets.
The biggest killers of mothers and their children in developing countries are diarrhoea, pneumonia and malaria. These can be prevented and treated.
However, a report by Grow Up Free From Poverty - a coalition of UK aid agencies - says not enough is being done to tackle these diseases.
According to the coalition, which includes the Catholic Agency for Overseas Development (CAFOD), Save the Children and Tearfund, extra money and better health policies could reverse the current trend.
Their report suggests that while some countries are making progress towards reducing unnecessary child and mother deaths others are not.
Some countries have failed to improve their mortality rates and others are going backwards, it said.
The report, which was presented to UK International Development Secretary Baroness Amos on Thursday, calls for the international community to do more.
George Gelber, chairman of the Grow Up Coalition and head of public policy at CAFOD, said the current situation cannot be allowed to continue.
"It is unacceptable that children continue to die from diseases that can so easily be prevented.
"Over the next 12 years, more than 80 million children and mothers will die if we fail to meet these targets - that's roughly the equivalent of the population of the United Kingdom and New York combined.
"The Grow Up coalition challenges all those with the responsibility and power to prevent these 80 million unnecessary deaths."
Regina Keith, health advisor to Save the Children and one of the authors of the report, said many of the deaths can be prevented.
"Most children in the developing world are suffering from illnesses that also affect children here in the UK.
"The difference is that in the developing world, many of these children will die."
She said helping each country to draw up better health policies would make a difference.
"While the responsibility for reducing the rate of child mortality should be shared globally, making it a reality must be based on locally determined priorities and not a 'one-size fits all' distribution of resources."
Speaking at the launch of the report, Reverend Agnes Mukandoli an aid worker in Rwanda accused the international community of ignoring the plight of people in developing countries.
"When a woman becomes pregnant she should be able to be happy and look forward to a new life coming into the world.
"But in my country, as in many others, the time of birth is associated with fear because so many mothers and babies die there from things that could be prevented.
"Their lives are not lost to complicated diseases - better basic healthcare, clean water and
sanitation would make a big difference.
"It seems that no one notices women and children dying. Are we invisible?
"It feels that way to us. Every minute another woman dies for no good reason. Half a million each year.
"We look to the powerful countries and people to stop this waste of life."